Conventional cable and satellite television transmission is evolving into interactive television or televideo (IT) systems. IT systems combine the video broadcast capability characteristic of conventional broadcast television with computer-executed applications or programming responsive to input from viewers. By some estimates, programming available from IT systems under development could include the equivalent of 500 channels of video broadcasting and unlimited numbers of interactive applications.
Conventional television broadcasting transmits a common or universal video signal simultaneously to all viewers associated with the network. In traditional aerial television broadcasting, each television station transmits a television signal corresponding to the programming available on one channel. In traditional cable television broadcasting, a cable television network operator receives video signals from multiple separate television stations or providers and rebroadcasts the various video signals on different channels of the cable television network. In both types of traditional broadcasting, the broadcaster controls the schedule for transmitting the universal television programming.
In contrast to such centralized scheduling of conventional universal television programming, IT systems provide dedicated programming services that transmit dedicated programming to individual viewers at times they request. An example of such dedicated programming services is sometimes referred to as video-on-demand (VOD). A VOD service transmits dedicated programming (e.g., a motion picture) to a viewer at a time requested by the viewer. A related dedicated programming service is preview-on-demand (POD). A POD service functions in cooperation with a VOD service, for example, to provide viewers with dedicated previews of programming available from the VOD service.
In one IT system implementation, available dedicated programming is stored in a digital format within a memory system in the IT system. In response to the viewer request, the IT system retrieves the selected programming from the memory system and transmits the programming to the viewer. In this type of implementation, the IT system uses a variety of IT system components such as computer processors, memory systems, and programming transmission systems to deliver programming to viewers.
IT system components or resources, like any physical system, have capacity limits. IT systems typically will not include resources sufficient to provide universal simultaneous transmission of dedicated programming to all viewers subscribing to the system. Such resources would be uneconomical and unnecessary because of the low probability that all subscribers would request dedicated programming services simultaneously. Accordingly, IT systems will include resources for providing dedicated programming transmission at some partial level of viewer usage, probably not exceeding regular peak levels of service. As an estimate it is expected IT systems could have resources to provide simultaneous transmission of programming to between 10 and 40 percent of system subscribers.
A consequence of such a system configuration is that viewer demands for dedicated programming services will sometimes exceed the IT system resources from providing such services. Under these circumstances, some requests for dedicated programming services would not be met. In some possible implementations, excessive demands on the dedicated programming service could result in disruption of programming delivery to some or all viewers. However, disruption of programming is highly undesirable.
In other implementations, dedicated programming services could be provided on a first-come, first-served basis according to the sequence in which viewers request the dedicated programming services. However, different dedicated programming services are expected to have premiums associated with them. For example, transmission of a conventional preview available from the POD service might generate for the IT system operator 10 units of revenue that is paid as an advertising fee by the programming provider. In contrast, a current-release motion picture available from the VOD service might generate for the IT system operator 200 units of revenue that is paid by the viewer requesting the programming. Accordingly, a disadvantage of a first-come, first-served basis of allocating resources is that dedicated programming of relatively low value (e.g., previews could dominate the dedicated programming service to the exclusion of higher value programming (e.g., full-length programming).